Is it possible to release for free, for a certain time, an application and when the time is expired sell the app with its original price again?I read that a similar things can be done by unpublish and republish with the new prices (free and not free).But in this way have I to change the package name? Will the user get the app's updates?Or worse, if the user uninstall the app, after the app it's been republished with a cost again he will have to re buythe app again? Another question is:I saw a site that has made a contest, and that site gives away, as a prize, copies of a paid application,how can it be done?